Oṁkāreśvaratīrtha (Omkareswaratirtha) is a famous tīrtha (tirtha; site of pilgrimage) belonging to Vārāṇasīkṣetra (Varanasikshetra).

Aiyangar Kṛtyakalpataru of Bhaṭṭa Lakṣmidhara((Tīrthavivecanakāṇḍa) p. 57)
Skandapurāṇa Vols. 1-7((Kāśī) 33.118)